CVE-2026-0715: Moxa Industrial Linux Secure DoS Flaw

CVE-2026-0715 Overview

CVE-2026-0715 is a Bootloader Vulnerability affecting Moxa Arm-based industrial computers running Moxa Industrial Linux Secure. The vulnerability stems from the use of a device-unique bootloader password that is provided directly on the device itself. An attacker with physical access to the device could leverage this information to access the bootloader menu via a serial interface, potentially causing operational disruption to industrial systems.

Critical Impact

While the bootloader enforces digital signature verification preventing malicious firmware installation, physical attackers could cause temporary denial-of-service conditions by reflashing valid images on affected industrial computers.

Affected Products

• Moxa Arm-based industrial computers running Moxa Industrial Linux Secure
• Devices with exposed serial interfaces for bootloader access
• Industrial computing equipment utilizing the affected bootloader configuration

Discovery Timeline

• 2026-02-05 - CVE-2026-0715 published to NVD
• 2026-02-05 - Last updated in NVD database

Technical Details for CVE-2026-0715

Vulnerability Analysis

This vulnerability relates to CWE-522 (Insufficiently Protected Credentials), where the bootloader password is stored or displayed on the device itself. The security issue arises from the password being accessible to anyone with physical access to the industrial computer, effectively negating the protection the password was intended to provide.

The attack requires physical proximity to the target device and access to its serial interface. While this significantly limits the attack surface compared to network-exploitable vulnerabilities, industrial environments often have multiple personnel with physical access to equipment, making insider threats or social engineering scenarios relevant attack vectors.

Importantly, the bootloader implements security controls that limit the impact of unauthorized access. Digital signature verification ensures that only Moxa-signed images can be flashed to the device, preventing the installation of malicious firmware or execution of arbitrary code. This defense-in-depth approach means the primary risk is operational disruption rather than complete system compromise.

Root Cause

The root cause of this vulnerability is the insufficient protection of bootloader credentials. By providing the device-unique password on the device itself, the credential becomes accessible to any individual who gains physical access to the equipment. This represents a fundamental weakness in the credential management approach, as the password fails to provide meaningful access control when it can be trivially obtained from the device it protects.

Attack Vector

Exploitation requires physical access to the affected Moxa industrial computer and the ability to connect to its serial interface. An attacker would:

1. Gain physical access to the target device
2. Locate the device-unique bootloader password provided on the device
3. Connect to the serial interface
4. Use the obtained password to access the bootloader menu
5. Potentially reflash a valid Moxa-signed image, causing a temporary denial-of-service

The physical access requirement significantly limits remote exploitation possibilities. Network-based attacks are not feasible for this vulnerability. The primary threat actors would include malicious insiders, individuals who gain unauthorized physical access to facilities, or attackers who have already compromised physical security measures.

Detection Methods for CVE-2026-0715

Indicators of Compromise

• Unauthorized serial connections to industrial computer equipment
• Unexpected device reboots or firmware reflashing events
• Physical tampering evidence on device enclosures or serial ports
• Anomalous maintenance activity logs indicating bootloader access

Detection Strategies

• Implement physical access logging and monitoring for areas containing affected industrial computers
• Deploy serial port activity monitoring to detect unauthorized connections
• Configure alerting for unexpected firmware update or device reboot events
• Review access control logs for personnel accessing industrial equipment areas

Monitoring Recommendations

• Enable comprehensive logging of all bootloader access attempts where supported
• Monitor device uptime and availability metrics to detect unexpected reboots
• Implement physical security monitoring including cameras and access badge systems in areas with affected equipment
• Establish baseline operational patterns to identify anomalous device behavior

How to Mitigate CVE-2026-0715

Immediate Actions Required

• Review and restrict physical access to all affected Moxa industrial computers
• Audit personnel access to facilities containing vulnerable equipment
• Implement or enhance physical security controls around serial interface access points
• Consult the Moxa Security Advisory MPSA-255121 for vendor-specific remediation guidance

Patch Information

Moxa has published a security advisory addressing this vulnerability. Administrators should consult the Moxa Security Advisory MPSA-255121 for specific patch availability, updated firmware versions, and detailed remediation instructions for affected industrial computer models.

Workarounds

• Physically secure serial interfaces by placing tamper-evident seals or covers over serial ports
• Implement strict physical access controls to limit personnel who can approach affected devices
• Deploy physical intrusion detection systems in areas containing vulnerable industrial computers
• Consider network segmentation and monitoring to detect any anomalous behavior from affected devices following potential tampering

Organizations should prioritize obtaining and applying official patches from Moxa while implementing these compensating controls to reduce risk exposure.